Work already completed suggests that the rabbit retina contains one or more synapses in which acetylcholine is used as a neurotransmitter. Further work will attempt to establish the location of this synapse. Electrophysiological experiments will characterize the ACh receptor of retina with respect to a series of classic cholinergic agonists and antagonists. Chemical experiments will seek a basis for a method of its morphological localization. BIBLIOGRAPHIC REFERENCE: Masland, R.H. and Ames, A. III. Dissociation of field potential from neuronal activity in the isolated retina: failure of the b-wave with normal ganglion cell response. J. Neurobiol. 6:305-312, 1975.